The safe transportation and storage of hazardous, high purity and ultra-high purity products are important in the manufacture of specialized components in the electronics and related industries. These transportation and storage procedures must meet all safety and environmental regulations set by government agencies in the countries and jurisdictions involved. In addition, transportation and storage methods must maintain the high and ultra-high purity requirements of the manufacturers that utilize these products.
Some of these products are used in moderate quantities and can be transported and stored in standard cylinders, for example, as compressed liquefied gases. As the demand for such high purity and ultra-high purity products grows, it becomes desirable to ship the products in larger, bulk containers which can be handled by standard modular shipping methods via truck, rail, ship, and air. As such containers become larger, the prevention of leaks and accidental emissions becomes correspondingly more important.
Modular transportation of these products in large volumes can be facilitated by mounting storage tanks within standard-sized structural frames which can be loaded and unloaded using standard cranes and lifts, and which can be shipped by standard modular shipping methods. It is desirable to maximize the volume of product in the tanks which are mounted in these standard-sized structural frames while meeting the safety, environmental, and product purity requirements associated with these shipping methods. These needs are met by the transportation and storage system of the present invention as described below and defined by the claims which follow.
The invention relates to a system for the transportation and storage of a product, which system comprises a tank including cylindrical wall section and two ends, wherein the cylindrical wall section and two ends define a cylindrical tank periphery, and wherein the tank periphery has an interior and an exterior. The system includes a recessed valve box having one or more side walls, a bottom wall, and a removable, sealable top cover which can be attached to the one or more side walls to seal the valve box. The valve box side walls are sealably joined to the cylindrical wall section such that the valve box extends through the cylindrical wall section into the interior of the tank periphery and is partially or totally disposed in the interior of the tank periphery. The system includes one or more valves disposed in the valve box, wherein each valve has a first and a second end, wherein each first end is connected to a pipe which passes through a wall of the valve box for introducing product into the tank or withdrawing product from the tank. The system further includes a rigid framework surrounding the tank and valve box, wherein the framework is attached to and supports the tank, and wherein the framework defines a periphery that encloses the periphery of the tank. The product in the tank is isolated from the atmosphere surrounding the tank when the valve box is sealed.
The valve box cover, when attached to the one or more side walls of the valve box to form a sealed valve box, may be disposed at the tank periphery or exterior to the tank periphery. The sealed valve box is isolated from the atmosphere surrounding the tank.
The system may further comprise means for either (1) introducing pressurization gas into the sealed valve box or (2) introducing purge gas into the sealed valve box and withdrawing purge gas from the sealed valve box.
The valve box may be cylindrical with a circular bottom wall, a circular top cover, and a cylindrical center portion forming a single side wall. The maximum allowable working pressure of the tank may be less than or equal to about 500 psia. The maximum allowable working pressure of the valve box when sealed may be equal to or greater than the maximum allowable working pressure of the tank.
Each second end of the one or more valves may be connected to a sealable closure which can be connected to a fill line for introducing product into the tank from an external source, connected to a withdrawal line for withdrawing product from the tank for external use, or sealed closed for transportation or storage of the product in the tank. Each sealable closure typically is disposed in the valve box and within the tank periphery.
The tank may contain a product in coexisting liquid and vapor phases, wherein a fill line is adapted for introducing liquid into the tank and a withdrawal line is adapted for withdrawing vapor from the tank. The tank may contain a product selected from the group consisting of ammonia, chlorine, hydrogen chloride, trichlorosilane, silicon tetrachloride, and methyltrichlorosilane.
Alternatively, the tank may contain a solid particulate component and gas, wherein the fill line is adapted for introducing a mixture of the solid particulate component and gas into the tank and the withdrawal line is adapted for withdrawing a mixture of the solid particulate component and gas from the tank. In another alternative, the tank may contain a slurry of a solid particulate component and a liquid component, wherein the fill line is adapted for introducing a slurry of the solid particulate component and the liquid component into the tank and the withdrawal line is adapted for withdrawing a slurry of the solid particulate component and the liquid from the tank.
The axis of the tank may be generally horizontal. In this embodiment, the tank has a top and a bottom, the valve box is disposed in the top of the tank, and a pipe connected to the first end of a valve forms a dip tube which extends through and downward from the valve box to a location adjacent the bottom of the tank.
The invention also relates to a method for the transportation of a product, which method comprises:
(a) providing a system which comprises
(1) a tank including a cylindrical wall section and two ends, wherein the cylindrical wall section and two ends define a cylindrical tank periphery, and wherein the periphery has an interior and an exterior;
(2) a recessed valve box including one or more side walls, a bottom wall, and a removable and sealable top cover which can be attached to the one or more side walls to form a sealed valve box, wherein the valve box side walls are sealably joined to the cylindrical wall section such that the valve box extends through the cylindrical wall section into the interior of the tank periphery and is partially or totally disposed in the interior of the tank periphery;
(3) one or more valves disposed in the valve box, wherein each valve has a first and a second end, wherein each first end is connected to a pipe which passes through a wall of the valve box for introducing product into the tank or withdrawing product from the tank, wherein each second end is connected to a sealable closure, wherein the valves and sealable closures are disposed partially or totally within the tank periphery, and wherein product in the tank is isolated from the atmosphere surrounding the tank when the valve box is sealed; and
(4) a rigid framework surrounding the tank and valve box, wherein the framework is attached to and supports the tank, and wherein the framework defines a periphery that encloses the periphery of the tank;
(b) at a first location, introducing product into the tank through at least one of the one or more valves, through a pipe connected to the first end of the valve, which pipe passes through the wall of the valve box and into the tank, and through a sealable closure connected to the second end of the valve;
(c) closing the one or more valves, sealing the sealable closure connected to each of the one or more valves, and attaching the sealable top cover to the one or more side walls of the valve box to seal the valve box;
(d) transporting the system from the first location to a second location; and
(e) at the second location, removing the sealable top cover to open the valve box, opening the sealable closure attached to the second end of one of the one or more valves, and withdrawing the product from the tank through the valve and through a pipe connected to the first end of the valve, which pipe passes through the wall of the valve box and into the tank.
While transporting the system from the first location to the second location, pressurization gas may be introduced into the sealed valve box. Alternatively, purge gas may be introduced into the sealed valve box while purge gas is withdrawn from the sealed valve box.
In another embodiment,the invention relates to a method for the storage a product, which method comprises:
(a) providing a system which comprises
(1) a tank including a cylindrical wall section and two ends, wherein the cylindrical wall section and two ends define a tank periphery, and wherein the periphery has an interior and an exterior;
(2) a recessed valve box including one or more side walls, a bottom wall, and a removable and sealable top cover which can be sealed to the one or more side walls to form a sealed valve box, wherein the valve box side walls are sealably joined to the cylindrical wall section such that the valve box extends through the cylindrical wall section into the interior of the tank periphery and is partially or totally disposed in the interior of the tank periphery;
(3) one or more valves disposed in the valve box, wherein each valve has a first end and a second end, wherein each first end is connected to a pipe which passes through a wall of the valve box for introducing product into the tank or withdrawing product from the tank, wherein each second end is connected to a sealable closure, wherein the valves and sealable closures are disposed partially or totally within the tank periphery, and wherein the product in the tank is isolated from the atmosphere surrounding the tank when the valve box is sealed; and
(4) a rigid framework surrounding the tank and valve box, wherein the framework is attached to and supports the tank, and wherein the framework defines a periphery that encloses the periphery of the tank;
(b) introducing the product into the tank through at least one of the one or more valves, and through a pipe connected to the first end of any of the one or more valves, which pipe passes through the wall of the valve box and into the tank, and through a sealable closure connected to the second end of the valve; and
(c) closing the one or more valves, sealing each sealable closure attached to the one or more valves, and attaching the sealable top cover to the one or more side walls of the valve box to seal the valve box.
The method may further comprise, after attaching the sealable top cover to seal the valve box, either (1) introducing pressurization gas into the sealed valve box or (2) introducing purge gas into the sealed valve box and withdrawing purge gas from the sealed valve box.